Improvement in tubular grates



UNITED STATES` PATENT OFFICE.

UMPROVEMENT IN TUBULAR GRATES.

Specification forming part of Letters Patent No. 47,053. dated March 28,1865.

To all whom it may concern.-

Be it known that I, ELI THAYER, of the city and county of Worcester, andState of Massachusetts, have invented a new and Improved Mode ofConstructing Tubular Gratos for Furnaces and Boilers; and I do herebydeclare that the following is a full and exact description thereof,reference being had to the accompanying drawings, and to the letters ofreference marked thereon.

The nature of my invention consists in so arranging tubular bars withvalves and stopcocks as to form a grate and to create and continue aconstant circulation of water or steam through the same, by means ofwhich the grate is kept at a low temperature, while the heat, which inordinary grates is only destructive, is by these means made useful inthe production of steam.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

Figure l represents so much of the tubing or steam-pipe as lies withinthe furnace and constitutes the grate. Fig. 2 represents a screen tocover and protect the grate from wear or injury. Fig. 3 represents aside view of the grate and the pipes connecting it with the boiler,together with the stop-cock g, the valve C, and the vent or blow-offcock h, also of the screen A, Fig. 2. Fig. 4 represents the front of thefurnace and the pipes through which the water enters the grate from theboiler and returns to the boiler from the grate.

In the construction of the grate I use very strong pipes, varying insize according to the length of the furnace and in distance apartaccording to the size of coal to be used.

The screen A, Fig. 2, may be made of wire, iron rods, perforated sheetmetal, or cast-iron, and may be in one piece or in sections. Its objectis to protect the grate, and, by making requisite a smaller number oftubes, to diminish the expense of the grate and to increase the draft ofthe furnace.

I will now proceed to describe the operation of my grate.

We suppose the boiler C to be filled with water above the flues or tosome point between f and 7c, Fig. 4. A tire is kindled either on thegrate-bars (Fig. l) or, if the the screen (Fig. 2) be used, on it. Theeffect of the heat will be to expand the Water in the tubes and tocreate steam in acertain portion of them. The force of this expansion orsteam will be exerted equally in each direction from the point where itis formed, a portion of its force being directed toward the point b,where the water enters the grate, and a like portion toward the point a,where the water or steam leaves the grate; but the force exerted in thedirection of the point b' raises the inverted valve c, which stops itsfurther action in that direction. Then the whole force of the steam andexpansion acts in the direction of the point a, Fig. l, and is continuedto the point 7c, Fig. 4, where the heated water or steam enters theboiler. As soon as the pressure in the tubes is thus relieved orapproaches an equality to that of the steam in the boiler, the valvec,Fig. 4, Will be forced down by its own weight and that of the column ofwater above it, and a new supply of water from the boiler will thus beadmitted into the grate, when the same action as above described will berepeated.

The passage of the Water or the steam through the gratewill always bemore or less rapid, according to the quantity of the hea-t in thefurnace above it. The bars will thus be kept at a low temperature.

Itis probable that the circulation through the grate will be so rapidthat no sediment can be deposited in it, but in case there should be, Iprovide for expelling it in the following manner: Close the stopcock g,which shuts off the Water from the grate, and open the vent or blow-oft`cock h. The steam from the boiler will then enter the pipe a k, Fig. 4,at the point 7c, and, passing into the grate at the point a, will gothrough the entire length of the tubing constituting the grate and passout at the point t, thus removing all obstructions.

There is also another method by which the same result can be eected-thatis, by combining on each side of the grate the pipes a lc and t' f, sothat the Water could be admitted to the grate for a certain length oftime at one end and then at the other, this change being made as oftenas should be found necessary to keep the grate clear.

The pipe a k and the pipe if are continuations of the pipe forming thegrate, the iirst being connected by an elbow-joint at the point bothWith the boiler and the vent-cook h, and

a and the other by a T-jont at the point b, the screen which covers andprotects the above the vent-cock h and belowT the valve c. grate, in themanner and for the purposes What I claim as my invention, and desireabove described.

to secure by Letters Patent is- The arrangement of the several partsherev ELI THAYER' in described7 viz.: the stop-cock g, the clieek-Witnesses: valve C, the vent-eoek h, the tube or pipe eon- S. P. POND.

stituting the grate, including its connections ELIJAH GRIsWoLD.

